STEORN DEMO LIVE & STREAM in Dublin, December 15th, 10 AM

[Omnibus]

@mondrasek,

I understand what you're saying and that's important but for the later stages. We're still at the point of proving that the coupling betwieen the rotor and the toroids is exclusively magnetic. That is, that the rotor doesn't use any of the input energy. That's a crucial point which needs utmost attention.

[Omega_0]

Did some research on core materials:

Relative Permeability chart:
Mild Steel (0.2 C)  2,000
Iron (0.2 impurity)  5,000
Silicon Iron           7,000
Mumetal               100,000
Purified iron (0.05 impurity) 200,000
Supermalloy           1,000,000
MetGlas                1,000,000

It seems, stuff like Metglas should be ideal for this kind of motor. It should need just microamps to saturate, which means one can have bigger cores , bigger magnets (=more output power) and only a few milliamps of input current.

Check the BH curve of Metglas here, its awesome
http://www.metglas.com/products/page5_1_2_6.htm

Here is a useful graph from which one can directly calculate the number of turns needed to saturate a particular core for some value of current:

http://en.wikipedia.org/wiki/File:Magnetization_curves.svg

So, say for steel core, you need 200 turns/inch to saturate it with a current of 0.1 Amp. If you are sending any more current than that, in this case, its not doing anything, just getting wasted as heat.

So the golden rule for input side is - highest permeability , correct number of turns (of as thick wire as possible) and optimal current.

[futuristic]

Wiki has also great info on "Magnetic susceptibility and permeability data for selected materials" :
http://en.wikipedia.org/wiki/Permeability_%28electromagnetism%29#Values_for_some_common_materials

[lumen]

Probably need the BH curve of the core material to determine what may work well.
Here is a nice pdf that explains some of the factors and how they could be used.

http://www.walkerscientific.com/Products/Product_Lines/Magnetic_Analysis/Hysteresisgraphs/Initial-4-Quadrant.pdf

I would recommend everyone read this if you don't already know this!

[futuristic]

I was thinking... could we use metal housing from an old hard drive to make toroids core.
It shoud have very high permeability to shield drive from outer magnetic fields.